Conventionally, a navigation device mounted on a vehicle has been known. The manufacturer of such a navigation device produces the hardware and programs therefor tailored to the specifications of individual customers (or dealers), who are automakers or car dealers, for example, and supplies the devices to the customers because the specifications of the navigation device vary from customer to customer. Therefore, even if the devices are of the same type, the map data and programs thereof may not be shared when the customer is different.
For this reason, a navigation device that can share a navigation system by selecting and exchanging the CD-ROMs used in various types of systems is developed (for example, see Patent Reference 1). This navigation device stores navigation processing programs, map information used for route search and route guidance, and other route information, which are compatible with various types of systems, in its CD-ROM, and its central processor retrieves the program supporting its own type of system from the CD-ROM, and reads the program into its program memory to start up the system, thus performing the navigation function. Accordingly, when plural types of systems share the CD-ROM, a navigation service freed from the system type can be provided.
Patent Reference 1: JP-A-09-053948
The conventional navigation device mentioned above is arranged such that a plurality of programs, which are compatible with the systems, respectively, are stored in a CD-ROM, and each of the systems acquires the program supporting its own type of system from the CD-ROM, and executes the program. Accordingly, the conventional navigation device can perform the navigation function adaptable to the device. However, the device cannot perform the navigation function suitable for an vehicle on which the navigation device is mounted, and for an environment in which the vehicle is used.
Moreover, the aforementioned conventional navigation device can be also arranged such that all the customers use the same type of hardware, for example, and the programs are provided for each of the customers, and are stored in a CD-ROM. However, it is necessary to store programs corresponding to the number of customers in the CD-ROM. When the number of customers increases, the quantity of data of the programs becomes enormous. Therefore, there develops a problem that the programs cannot be stored in the CD-ROM.
The present invention has been accomplished to solve the above-mentioned problem. An object of the present invention is to provide a navigation system that can perform navigation suitable for the vehicle and the use environment in which the vehicle is used by use of a small quantity of data.